(1) Field of the Invention
The present invention relates to bags for use in storing and transporting bulk materials such as free-flowing powders and granules, particularly a bag having an opening formed in the top portion thereof, and the present invention also relates to a process for manufacturing such a bag.
(2) Description of the Prior Art
In known bags having an opening for filling a material, formed in the top portion thereof, the material-filling opening and the top end cover are separately prepared and sewn together, and the top end cover is then sewn to the bag proper. Accordingly, the sewing operation is very troublesome and the efficiency of the sewing operation is very low.
The top end cover is sewn to the bag proper along the entire length thereof to form a seam. This seam can be broken or loosened by an impact or shock occurring during the loading operation. Accordingly, from the viewpoint of safety, it has been desired to improve the quality of these bags.